清道光乙酉年（1825年） 白芙蓉石閒章 《木居士中溶刻》款

印文：不及則亦不失於令名

In overall good condition except for a minute bruise to the outer edge of the seal face, and minor nicks along the edges. The actual color of the stone is warmer than the catalogue photo.
In response to your inquiry, we are pleased to provide you with a general report of the condition of the property described above. Since we are not professional conservators or restorers, we urge you to consult with a restorer or conservator of your choice who will be better able to provide a detailed, professional report. Prospective buyers should inspect each lot to satisfy themselves as to condition and must understand that any statement made by Sotheby's is merely a subjective qualified opinion.
NOTWITHSTANDING THIS REPORT OR ANY DISCUSSIONS CONCERNING CONDITION OF A LOT, ALL LOTS ARE OFFERED AND SOLD "AS IS" IN ACCORDANCE WITH THE CONDITIONS OF SALE PRINTED IN THE CATALOGUE.

Mu Jushi is the sobriquet of Qu Zhongrong (1769-1842). Qu passed the imperial examinations in 1814 and was appointed judicial secretary of the provincial administration commission in Hunan. Apart from being an official, he was also known as a painter, calligrapher and seal carver.

Baifurong stone is characterized by its close resemblance to jade, and like tianhuang, was mined in the Shoushan area in the Fujian province.  By the late Qing dynasty, baifurong had become rare and highly valued, and was listed, together with tianhuang and Changhua stone as the 'Three Treasures' of seal stones. 

Compare a pair of 18th century baifurong seals sold in our Hong Kong rooms, 9th October 2007, lot 1515.